360 procharged

Hi all! I got a screaming deal on a complete procharger setup with water injection and a free aeromotive a1000 fuel pump and regulator. Originally, I was going to do a turbo setup but because of fabrication and the deal on this procharger I couldn't pass it up. I have a question- my 360 has forged pistons but arp bolts in the stock rods and mains. My head gaskets are mls but 0.090 thick, how much boost would you say I could get away with and be safe? I will be running 91 octane. This setup should be nice considering my last time out I went 13.7@98mph in 8600 D/A. Hope to be in the 12s on low boost :)